In QuintaDB you can hide any form field from integrated widget. This way you can show only allowed fields in widget and other fields only inside QuintaDB as admin.
Email newsletters
If you have online database, which contains email column, you most probably will want to send email newsletter to this email. As well as use some data from database in this email, like Name column. Now this is possible in QuintaDB's email newsletter
How to link forms in QuintaDB
In order to link tables in QuintaDB you have to add Relationship field in Fields menu and configure it.